Multiple-switch-board apparatus



(No Model.)

- .J. J. OARTY. I MULTIPLE SWITCH BOARD APPARATUS.

No. 427,155. Patented May 6, 1890.

UNITED STATES PATENT OFFICE.

JOHN J. CARTY, OF NENV YORK, N. Y., ASSIGNOR TO THE IVESTERN ELECTRICCOMPANY, OF CHICAGO, ILLINOIS.

MULTlPLE-SWlTCH-BOARD APPARATUS.

SPECIFICATION forming part of Letters Patent No. 427,155, dated May 6,1890.

Application filed October 26, 1889.

To all whmn it may concern:

Be it known that I, J QHN J. CARTY, a citizen of the United States,residing at New York, in the countyof New York and State of NewYork,

have invented a certain new and useful Improvement inMultiple-SWitch-Board Apparatus, (Case 7,) of which the following is afull, clear, concise, and exact description, reference being had to theaccompanying drawing, forming a part of this specification.

My invention relates to telephoneexehange apparatus, and is designed foruse in those exchanges in which multiple switch-boards are employed.

The special object of my invention is to simplify the switch-boardapparatus, in order that more lines may be brought within a given spaceupon the switch-board. My invention is therefore of special utility inlarge exchanges.

Briefly stated, my invention consistsin connecting the telephone-linesin pairs with the different switches on the switch-board, a singleseries of spring-jack switches serving for two lines, one line beingconnected with the spring of each of its series on the differentswitch-boards and the other line of the pair being connected with theframes of the switches of the same series.

My invention consists, further, in the keyboard apparatus, whereby theconnections and disconnections are made between the lines of thedifferent subscribers, a feature of this key-board-apparatus inventionbeing providing sets of cords and plugs at the different boards, eachset consisting of three plugs and their cords, one of said plugs being asingle connecting-plug and the other plugs of each set being loop-plugs,the con- 0 nections of the loop-plugs being so disposed that one of saidloop-plugs will be adapted to make connection with one line of a pair,while the other loop-plug will be adapted to make connection with theother line of the pair. Several such sets of plugs and cords, withappropriate loop-keys and calling-keys, are provided at each of theseveral switchboards. The loop-plugs may be of the same construction.Their connections, however, will be different, the tip of one being inC-O 11 nection with the cord of the single plug, while Serial No.328,289. (No model.)

the sleeve of the other is in connection with the single plug, theremaining terminal of each plug being provided each with a connection toa different special switch. We have, then, 5 5 a circuit from the singleplug which is branched to one terminal of one of the loopplugs and toanother terminal of the other loop plug. The strands of the loop -plugswhich are not thus connected with the single plug I have sometimestermed the idle strands, because ordinarily they will have no functionexcept when after connection has been made with one of a pair oftelephonelines it is desired to make connection with the other line ofthe pair at the same board. In order that this may be done, I haveprovided the connection for each of the idle strands of the loop-plugs,at which connections or switches the other wire of a pair when thuswanted may be made accessible for tests and connections.

The telephone-lines, as before stated, are arranged in pairs. Thecircuit of one line of a pair extends normally from ground at thestation thereon through the bell at said station and thetelephone-switch to a key, and thence normally to the springs of theswitches or connecting devices on the different boards and to itsspecial connecting-key oranswering- Switch upon one of the boards. Theother line of the pair extends from the ground at its station in thesame manner through the bell, telephone-switch, and key, and thence tothe central office, where itis connected with the other 8 5 portion-thatis to say, the frame of each of the same switches on the differentswitchboards and thence to'its special answeringswitch. The two linesare thus normally open at the central office. In order that thesubscribers may call the central office, I provide, preferably, acircuit extending to a number of stations so arranged that a subscriberat any of these stations may, by taking down his telephone and pressinga key, bring his tele-. phone into this circuit, this circuit includingU alistening-operators telephone at the central station. Any one ofseveral subscribers, on thus taking down his telephone and pressing thekey, may speak directly to the listening I00 operator.

My invention will be readily understood by reference to the accompanyingdrawing, in which I have shown the circuits of a pair of telephone-linesextending from the stations thereon, each through the different portionsof a series of switches on different switchboards, the commoncalling-circuit connecting said stations with the listening; operator,the key-board apparatus being shown at one of the switch-boards.

The circuit a of station 1 extends through thebell and switch at saidstation, and thence through a key a, and thence to the central office,where it is connected with the spring a of the switch on the first boardwith the spring a of the other switch of the series on the last board,and thence the circuit of line a extends to the connecting or answeringswitch a", which is placed in this instance on the last board. Thecircuit of the line b of station 2 is connected in the same mannerthrough thesubscribers apparatus at said station 2 to a key Z), and fromthe key I) circuit 1) extends to the central office, where it isconnected with the portion 19 of the switch of the pair on the firstboard, and thence to the portion Not the other switch of the seriesbelonging to the pair on the last board, and thence to its specialanswering -switch Z). These lines a and b may be said to constitute apair of telephone-lines. Other pairs of telephone-lines will beconnected in a similar manner with each of the switch boards. Thus line0 is connected with the portions 0 c of another series of spring-jackswitches and with the special answering-switch c, in this instanceplaced on the first board. The other line d of the pair is connectedwith the portions (1 d of the same series of switches and with theanswering-switch (1 upon the first board. The common calling-circuit 6extends through both the stations 1 and 2. Fifty or one hundred stationsmay thus be connected with one common signal-wire. This wire 6 isconnected through the listeningoperators telephone to ground. Anysubscriber, by means of his key, as keys at b, may put himself incommunication with the listening operator and give his order direct. Thetest-plug f has its shank insulated. The cord f of this plug isconnected througha coil of the converter f to ground, the other coil ofthe converter being bridged across the terminals of the telephone. Theplugs g, g, and g constitute a set of plugs. Each operator will beprovided with several such sets.

Usually ten sets will be sufficient for eachoperator. The plug g is asimple single plug. The plugs g and g are loop-plugs and may each be ofthe same construction, as shown. Each set of plugs is connected togetherby strands of flexible cords. A usual loop-switch g is provided formaking connection with the operatorfs telephone. The single plug 9 isconnected through the calling-key g and the test-battery g to thecontact of calling-key g. From the calling-key g are two branches, onebranch connectingthrough a strand of the cord of plug g to the tip ofsaid plug 9 The other branch g is connected with the strand of the cordof plug g, which connects with the sleeve thereof-that is to say, thebranches g are connected the one with the tip of one of the loop-plu gsand the other with the sleeve of the loop-plug. Now the switches uponthe switch-boards are of such construction that the sleeve of aloop-plug connects with one portion thereof,while the tip connects withthe other portion thereof. Thus, suppose plug inserted in the switch ofline a upon the last board. It is evident that the tip thereof will comeagainst the spring a and thus the circuit, including the cord of thesingle plug, will be closed through the strand or branch 9 to the tip ofplug 9 and thence to the spring a of the switch, and thence to the linea. Suppose; now, instead of inserting plug 9 I insert plug g. In thiscase the cord of the single plug .g will be connected in circuit by thestrand g with the sleeve of plug g, and from said sleeve with theportion b of the switch, and thus with the telephone-line 1), connectingwith said portion Z). Thus, by inserting the loop-plug g in a socket,connection will be made with one of the lines connected therewith, andby inserting the other plug g in the same socket-connection will be madewith the other line connected with said socket. The strands g and g ofthe loop-plugs are run ordinarily each to a special connecting device. Ihave not, however, deemed it necessary to show each of these strands g 9connected with a special socket or connecting device, as suchconnections and connecting devices are shown with the correspondingstrands of the other set of plugs illustrated. This other setconsists ofa single plug it and the loop-plugs h 712.

The telephone-line c is shown connected with the telephone-line a bymeans of the sin gle plug h, inserted in the answering-switch a of linea, and the loop-plug 7L2, inserted in the switch, as shown, to connectits tip with the spring or portion 0 with which line 0 is connected. Thecord of plug 71 is connected through the test battery lbs, and thence tothe strand h of plug 7L2, which strand connects with the tip of saidplug. The other strand 7L5 of the cord of plug 71 connects with thespecial connecting device 72 Thus, when connection is made with line 0,there will be an open branch from line d, the circuit of which may betraced from the portion d of the switch to the sleeve of plug 7L2, andthence by strand 71 to connecting device h. The object of this is toafford means for making connectionwith line d at the same board at whichconnection has been made with the line 0 of the pair. If the plug h wereinserted in 'a switch, the plug h would be connected by the strandthereof to branch It? and thence to the strand connecting with thesleeve of plug it. The strand 7L8 would then be whatI term the idlestrand of plug 71/. This strand its is provided with a connection 7L",extending to the connecting device h Thus the idle strand of eachloop-plug is provided wit-h a connection extending to a switch orconnecting device. Thus,when either of the plugs is inserted in a switchto connect with one line of a pair, connection may be made with theother line of the pair when called for at the same board at theconnecting device of the idle strand of the plug which is in use. Thus,suppose after lines a and e have been connected together, as shown,subscriber at station 2 should call for connection with line d. Theoperator would insert plug 9 of another set of plugs in answering-switchb and with test-plug f applied to this connecting device 71 would testline (I, and finding line d free would immediately insert one of theplugs g g in the switch h. In this case either plug g or g might beused. The idle strands g g in this instance have no function.

Having thus described my invention, I claim as new and desire to secureby Letters Patent 1. A pair of telephone-lines extending each from adiiferent subscribers station, each to a difierent corresponding portionof a series of switches, each switch being on a different switch-board,in combination with a set of plugs and cords at each of theswitch-boards, said set consisting of a single plug and two other plugs,to different terminals of which the single plug is connected, wherebythe switchman may connect either of said pair of lines with the singleplug, substantially as and for the purpose specified.

2. A pair of telephone-lines, each connected with a different portion ofthe same switch upon the switch-board, and two plugs each having aterminal connected with a common wire, the terminal of one plug beingadapted to connect with one portion of the switch and the terminal ofthe other being adapted to connect with the other portion of the sameswitch, whereby either of said pair of telephone-lines may be connectedwith the common line by using one plug or the other, substantially asand for the purpose specified.

3. A set of plugs and cords consisting of a single plug having branches,one branch extending to the tip of one loop-plug and the other branchextending to the sleeve of another loop-plug, the remaining terminals ofeach of said loop-plugs being provided each with a branch connection todifferent connecting devices, substantially as and for the purposespecified.

I11 witness whereof I hereunto subscribe my name this 5th day ofOctober, A. D. 1889.

J OHN J. CARTY.

Witnesses:

O. G. I-IAWLEY, ELLA EDLER.

